1. Technical Field
The present invention relates to lens drive devices, and in particular, is preferably suitable for use in lens drive devices for focus adjustment incorporated into cameras, camera-equipped cell phones, and others.
2. Description of the Related Art
Conventionally, lens drive devices are incorporated into cameras and others for focus adjustment. Some of those lens drive devices use a magnetic driving force to drive a lens part in a direction of an optical axis. In this case, a magnet is attached to a lens holder, and a coil is attached to a base for retaining the holder, for example. By applying an electric current to the coil, an electromagnetic driving force is generated between the magnet and the coil. This electromagnetic driving force drives the holder in the direction of the optical axis of the lens.
In such a lens drive device, the magnet may be attached to an outer peripheral surface (side surface) of the holder. In addition, the coil is disposed in such a manner as to surround the entire outer periphery of the holder. A box-shaped cabinet covers these holder and coil.
A lens drive device for cell phone or compact camera needs to be reduced in size. However, since the coil is supposed to surround the entire outer periphery of the holder as stated above, it is necessary to secure a space for the coil to be situated between the lens and the holder over the entire periphery. This makes it difficult to downsize the lens drive device in a direction perpendicular to the optical axis of the lens.